As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the Audizine Family today!

If you're new to forums in general, be sure to check out the Forum FAQ. To start viewing posts, select the forum section that you want to visit from the selection below.

Blowby even with catchcan in place?? Can anyone shed some experience?

Iíve had this catchcan for some time. This particular catchcan is a Baffled Type (advertised as anyway) deletes the PCV valve completely and I installed a drain valve underneath and drain it once every fortnight. There is always oil that can be drain out each time, so I assume it works correctly (no PCV/Diagrams in place, means that all the blowby/ventilation will no go into the catchcan, than being managed by a PCV)

Recently, it is the first time ive ever had to open the Rubber throttle intake hose, as Iíve conducted a few CRC GDI Intake Valve aerosol cleans to remove carbon and this location is the closest/ most suitable area. (before the throttle body and after the Air-noise-Dam, circled in RED).

Ive noticed it on first time and wiped it off and it re-appeared on 2nd time (within 2 weeks) this form of stagnant light-colored oily residue (see pic)
I canít think of anything other than it being Blowby. But why, shouldnít it be eliminated with this set up?

It's oil residue from the turbo. It collects in places like the bottom of the intercooler, turbo muffler, and where the diverter valve is. It's most noticeable if you had an aftermarket atmospheric blow-off valve. You'll see oil residue all over the vent holes of the valve.
Since you don't have one, the oil vapor collects in places, and eventually makes it's way up to the intake manifold, where it eventually is run through the motor & burned..
Kind of a common thing with turbocharged engines. If you were losing a lot of oil (say a quart a month) I'd be concerned. But it's a normal thing. I have a '14 Allroad, does the exact same thing. The DV+ and blow-off valve on my engine usually has a nice coating of light oil on it, by the time I change my oil (usually around 2500 miles)

It's oil residue from the turbo. It collects in places like the bottom of the intercooler, turbo muffler, and where the diverter valve is. It's most noticeable if you had an aftermarket atmospheric blow-off valve. You'll see oil residue all over the vent holes of the valve.
Since you don't have one, the oil vapor collects in places, and eventually makes it's way up to the intake manifold, where it eventually is run through the motor & burned..
Kind of a common thing with turbocharged engines. If you were losing a lot of oil (say a quart a month) I'd be concerned. But it's a normal thing. I have a '14 Allroad, does the exact same thing. The DV+ and blow-off valve on my engine usually has a nice coating of light oil on it, by the time I change my oil (usually around 2500 miles)

Heya,

Thanks for your response. So is your Allroad 14' have the gen 2 or the Gen 3?

Do you also have a catchcan?, I thought having one will alleviate or even overcome this issue completely?

So what youíre describing is that for our motors, even with a catchcan and or good PCV... this residues is normal?

With the catch can system replacing the PCV and the paths from the PCV to the turbo and intake manifold, his belief is that there should now be no path for oily crankcase gases back to the intake tract.
The engine does use internal EGR, whereby combustion chamber contents flow back into the intake manifold. I am not sure if that would contain sufficient liquid content to leak past the throttle plate back and down that hose.
The B8 platform never used the EA888 gen 3. That engine arrived with the B9 platform. Though it had already been in service for several years with VW.

It's a CPMB (EA888 - Gen 2) Flex Fuel/ E85 engine.
I don't run a catch can. I'm always up in New Hampshire, Maine, and Vermont in the winter months (skiing & snowboarding). The cold weather accelerates the moisture that accumulates in the catch can, and has to be emptied a bit more often in the winter. No big deal though.
The catch can does a great job, but its not a 100% cure all for everything in the intake tract of the engine.
You will unfortunately get a small amount of oil vapor/residue in the areas I mentioned in my last post.
You don't have to clean the hoses, throttle body and all the other places I mentioned, but if you did clean them once a year, it doesn't hurt anything.
I usually take my diverter valve/blow off valve every 6-7000 miles to clean & inspect it. Not needed, but I like to keep things surgically clean under the hood, and prevent problems if I can. Especially when I'm travelling 3-6 hours depending on where I go skiing/snowboarding.

It's a CPMB (EA888 - Gen 2) Flex Fuel/ E85 engine.
I don't run a catch can. I'm always up in New Hampshire, Maine, and Vermont in the winter months (skiing & snowboarding). The cold weather accelerates the moisture that accumulates in the catch can, and has to be emptied a bit more often in the winter. No big deal though.
The catch can does a great job, but its not a 100% cure all for everything in the intake tract of the engine.
You will unfortunately get a small amount of oil vapor/residue in the areas I mentioned in my last post.
You don't have to clean the hoses, throttle body and all the other places I mentioned, but if you did clean them once a year, it doesn't hurt anything.
I usually take my diverter valve/blow off valve every 6-7000 miles to clean & inspect it. Not needed, but I like to keep things surgically clean under the hood, and prevent problems if I can. Especially when I'm travelling 3-6 hours depending on where I go skiing/snowboarding.

With the catch can system replacing the PCV and the paths from the PCV to the turbo and intake manifold, his belief is that there should now be no path for oily crankcase gases back to the intake tract.
The engine does use internal EGR, whereby combustion chamber contents flow back into the intake manifold. I am not sure if that would contain sufficient liquid content to leak past the throttle plate back and down that hose.
The B8 platform never used the EA888 gen 3. That engine arrived with the B9 platform. Though it had already been in service for several years with VW.

Sorry I didnít mention I am From Sydney Australia, not sure about North America, but the B8.5 2014 2.0T models came with Gen 3 over here, see below attached as an example. (also 7-Spd DSG Gearbox like on mine was available for B8.5 Gen 2, which I think different slightly to over there.

So the catchcan, even in theory, where it should eliminate PCV and all Blowby paths... wonít help the internal EGR design?
If so, thatís still potentially pretty bad... and Iíve heard fumes alone can cause carbon desposits. Probably why our cars are so bad with build up.

Originally Posted by porwal22

It's a CPMB (EA888 - Gen 2) Flex Fuel/ E85 engine.
I don't run a catch can. I'm always up in New Hampshire, Maine, and Vermont in the winter months (skiing & snowboarding). The cold weather accelerates the moisture that accumulates in the catch can, and has to be emptied a bit more often in the winter. No big deal though.
The catch can does a great job, but its not a 100% cure all for everything in the intake tract of the engine.
You will unfortunately get a small amount of oil vapor/residue in the areas I mentioned in my last post.
You don't have to clean the hoses, throttle body and all the other places I mentioned, but if you did clean them once a year, it doesn't hurt anything.
I usually take my diverter valve/blow off valve every 6-7000 miles to clean & inspect it. Not needed, but I like to keep things surgically clean under the hood, and prevent problems if I can. Especially when I'm travelling 3-6 hours depending on where I go skiing/snowboarding.

I donít recall my previous car (Also a turbo) a Lancer Evolution IX has any residue like this.. but I guess even turbo cars differ.

So in your experience with both proper functioning PCV or experiences with Catchcans, this residue is always present for this car?

Interesting. I wonder why Audi bothered building the A4 with different 2.0T motors at the same time. US, can't say for CA and MEX, didn't see the Gen 3 in an A4 until the B9 arrived in 2017. Love those wheels, btw.
No idea what "normal" should be in a modified car. And that you have a Gen3 will make yours different than 95%+ of the B8 A4's discussed here. The only other source of material being added to the intake tract if you've removed the PCV connections is the EVAP, but that shouldn't have any oil content.

I donít recall my previous car (Also a turbo) a Lancer Evolution IX has any residue like this.. but I guess even turbo cars differ.

So in your experience with both proper functioning PCV or experiences with Catchcans, this residue is always present for this car?

From my understanding the carbon buildup most modern vehicle is experiencing is due to the combination of direct port injection and the vehicles recirculating systems. Because of these recirculating systems, some contaminated vapors always make it back to the intake system. With your old EVO IX the reason you probalby don't see any carbon build up is they're probably Port injected rather than direct injection. Meaning the injectors spray fuel on the intake port behind the intake valves and not directly into combustion chambers. So in a sense Port injetion helps cleanup the valves from having carbon buildup. Now most modern audi's (and a lot of modern cars) are direct injection. Meaning the injectors are spraying directly into the combustion chamber ( this is more efficient ) but the drawbacks are your valves won't get sprayed with fuel and hence carbon starts to buildup.

Btw this isssue is not unique to audi's, in fact a lot of vehicles with direct port injection have carbon buildup issues. It's such a common thing that this has just become part of the maintenance for these types of vehicles.

Interesting. I wonder why Audi bothered building the A4 with different 2.0T motors at the same time. US, can't say for CA and MEX, didn't see the Gen 3 in an A4 until the B9 arrived in 2017. Love those wheels, btw.
No idea what "normal" should be in a modified car. And that you have a Gen3 will make yours different than 95%+ of the B8 A4's discussed here. The only other source of material being added to the intake tract if you've removed the PCV connections is the EVAP, but that shouldn't have any oil content.

Yeah it is a bit odd with different Audis internationally. What always baffles me is how the B8.5 A4's in North America was equipped with the 4-post style steering wheels that were seen on B8.0. When the rest of the word had the more stylish/round steering wheel (as pictured in the Australian CarSales link for e.g)

The one in the carsales isn't my car, but was just trying to show an example of an engine bay of a B.85 with Gen III. (I do also have the 5-rotor arm OEM wheels, painted Black; which looks even better. But ill show you in private MSG to avoid going off-topic here).

Originally Posted by Blur2u

From my understanding the carbon buildup most modern vehicle is experiencing is due to the combination of direct port injection and the vehicles recirculating systems. Because of these recirculating systems, some contaminated vapors always make it back to the intake system. With your old EVO IX the reason you probalby don't see any carbon build up is they're probably Port injected rather than direct injection. Meaning the injectors spray fuel on the intake port behind the intake valves and not directly into combustion chambers. So in a sense Port injetion helps cleanup the valves from having carbon buildup. Now most modern audi's (and a lot of modern cars) are direct injection. Meaning the injectors are spraying directly into the combustion chamber ( this is more efficient ) but the drawbacks are your valves won't get sprayed with fuel and hence carbon starts to buildup.

Btw this isssue is not unique to audi's, in fact a lot of vehicles with direct port injection have carbon buildup issues. It's such a common thing that this has just become part of the maintenance for these types of vehicles.

I do appreciate you explaining the concept of GDI engine. Yes I am well aware of carbon build up and is mostly caused by the design flaw of direct injection. Hence why some manufacturers (incl Audi) are now going both Multi+Direct injection, where they are still retaining direct injection (for all the benefits, especially Emission purposes) and another fuel source prior like multi-port. I believe most of the Gen III, S3s and B9s are dual injected.

This is the whole reason I found out about this residue sitting there on the pipe, I've now used x4 CRC GDI Intake & Turbo Cleaner Aerosol cans within 3 weeks. (Unfortunately, I don't have a Boroscope to show everyone here results. but I can tell you it feels like it gave the car a new lease of life after the initial clean)

I know the GDI problem is not unique to Audi.. but the funny thing is; if you do searches online & Youtube... many manufacturers that make GDI cars don't seem to have the problem. For e.g I was curious and searched for the 'C63 AMG carbon build up' on Youtube and Google. as I heard they (both the current model and the previous are BOTH just direct injection and not Dual injection) and nothing ever came up about them, even on older models.
But guess what came up when I did that particular search though?... Literally every result was the Audi 2.0T TFSI + BMWs and some Hyundai's

Originally Posted by FlyPenFly

Intake carbon build up is actually mostly from combustion blow by in the Audi/VW DI engines. Very little to no difference with catch cans.

Well apparently that's what the catchcans are meant to be for, to eliminate/reduce blowby.

what I would love is someone who is aware they have a functioning/good condition PCV and opening that Throttle Intake pipe and having a look. If its present on theirs, then its likely this is what happens on all these cars and the Catchcan cannot alleviate this problem.